A work tool, such as cutting pliers, a cutting nipper or pruning clippers includes two pressure-nipping members being overlapped one on top of another and joined at respective mid-sections thereof so as to be crossed and pivotable with respect to each other, an active section at a distal portion thereof for a nipping, cutting or bending operation, and a gripping section at a proximal portion thereof for allowing an operator to grip.
The work tool is used for performing a predetermined work at the active section that opens and closes in conjunction with the opening and closing operations of the gripping section, and are generally provided with a spring which urges the gripping section in the opening direction for improving operability of the gripping section, that is, to save energy for the opening operation at the gripping section done by the operator.
However, when the spring is employed, a resilient force thereof may be lowered or the spring may be damaged due to aged deterioration of the spring, and hence it is necessary to replace the spring periodically. In order to protect the operator from thecitis, it is desirable to reduce a force required for the operator to close the gripping section, that is, the elastic coefficient of the spring. However, when the elastic coefficient of the spring is reduced to a certain extent, there arises a problem such that a repulsive force sufficient for opening the closed gripping section by the spring cannot be obtained.
On the other hand, employment of a magnetic force of a magnet instead of a resilient force of the spring in the related art is proposed.
In other words, disclosed in Patent Document 1 is a tool in which magnets are provided at a pair of proximal ends of the gripping section of the two pressure-nipping members with the same pole faced to each other, and a repulsive force are generated when the pair of proximal ends come close to each other.
A tool disclosed in Patent Document 2 is further provided with a switching function in which a magnet on one of the pressure-nipping members rotates to maintain a state in which the pair of proximal ends of the gripping section attract each other and the active section is closed when being stored.
The work tools in which the magnets are employed are provided with the magnets at the pair of proximal ends of the gripping section. However, the attracting force or the repulsive force of the magnet is in inverse proportion to the square multiple of the distance between the magnets and there are not many work tools in heavy usage in which the pair of proximal ends of the gripping sections come close to each other to an extent which is abutment, and they are apart from each other in many of them. Therefore, even though the magnets are provided at the pair of proximal ends of the tool in this configuration, it is difficult to obtain a sufficient repulsive force after the gripping section is gripped.
In the work tool described in Patent document 2, since the magnets (the pair of proximal ends) are apart from each other even at the time of storage, the attracting force is small, and hence they do not have sufficient practicability. When magnets of strong magnetic force are employed to increase the repulsive force or the attracting force, since the respective magnets are located at ends of the tool, in particular, the magnet on the rotating side is located on the outside of the gripping section, metallic members such as other tools are attracted easily. Therefore, it is very troublesome to remove the attracted members.    Patent Document 1: JP-A-53-130600    Patent Document 2: JP-UM-B-60-1983